3,535 research outputs found
Daily variations of water use with vapor pressure deficit in a plantation of I214 poplars.
Daily rates of whole tree water use were measured in a homogeneous 7-year-old plantation over 84 days. Two trees were selected in the two most contrasting ends, i.e., with mean water table at -1.5 m and -3.5 m. Results showed that the mean tree water use was close to 80 dm3 day–1 with a small mean difference between the two sites (5.4 dm3 day–1, about 7%). Higher daily variations were observed on a single tree over the season (from 17 to 138 dm3 day–1). These fluctuations could be modeled using linear regressions on the vapor pressure deficit (VPD). Results also indicated decreasing sap flux densities with radial sapwood depth and that the whole tree water use could be estimated from the sap flux densities measured at the 0–2 cm depth
Molekularbiologische Affinitätsstudien : neue Anwendungen elektrophoretischer, miniaturisierter Trennsysteme
Molecular biological affinity studies is a field with an abundance of interesting
analytical methods. The following work summarises the current methods in a short
overview before focussing on the electrophoretic measurements. They belong to an
active area of research, which is suitable for a large spectrum of applications. The
possibility to transfer affinity studies from capillary to a miniaturised system – the chip
– is the main aim of this work. In the age of high throughput screening, fast new
analytical methods are required and miniaturised systems, such as the
electrophoretic chip, become a common demand.
Up-to-now the application of EMSA (electrophoretic mobility shift assay) was only
used on capillary. Here it was successfully transferred for the first time to a planar
miniaturised system. In order to characterise the microchip, known systems
(neurotransmitters and cyclodextrins) have been measured. As for the binding
parameters, the measurements proofed that chips deliver the same results as the
capillary, however in a shorter time and with less material consumption.
Apart from measurements with neurotransmitters, studies with artificial receptors and
peptides, with single-stranded DNA and metal cations have been accomplished. The
results of the binding affinities have been compared to calorimetric measurements
and confirmed the quality of the ACE (affinity capillary electrophoresis)
measurements on chip. By choosing certain oligonucleotide sequences and suited
buffer systems, the binding selectivity of metal ions for tetranucleotides could be
shown. Considering the building of binary and tertiary complexes, which depends on
the kind of buffer molecules, the binding constants and the amount of binding
partners were calculated. Although not the same number of measurements has been
compiled for the microchip as for the capillary, in principal the suitability of the chip to
examine non-covalent bindings to oligonucleotides and DNA strands was shown.
Methodical specialities as well as qualitative differences between
measurements on the capillary and on the chip have been observed and
documented. In some areas of research, important for electrophoretic ACE
measurements, chips are superior to capillary. The smaller amount of probes and
buffer and the shorter separation time, which allows the measurement of instable
systems, all speak in favour of the chip. Due to the significantly shorter separation
times, the phenomenon of diffusion has a distinctly smaller impact on the peak
broadening. This improves the separation efficiency. High separation efficiency is
important for ACE analytics, especially so when the separation is done in seconds.
The worse sensitivity of the chip could only be put down to technical peculiarities and
less efficient detection systems of the chips used here. Although capillaries with
normal separation lengths deliver qualitatively better results at the moment, the
microchip will be superior to the classical capillary electrophoresis as soon as reliable
injection methods are available and the steering of probe and separation media are
solved, additional to its present advantages
Le gradient entre la pression pulmonaire artérielle diastolique et la pression pulmonaire d'occlusion est important dans l'évaluation des hypertensions pulmonaires post- capillaires
Les hypertensions pulmonaires post-capillaires sont définies par une pression artérielle moyenne (PAPm) ≥ 25mmHg et une pression pulmonaire d'occlusion (PAPO) > 15mmHg. Une augmentation de la PAP peut être soit passive, transmission rétrograde de l'augmentation de la pression du coeur gauche ( gradient transpulmonaire GTP ≤ 12mmHg), soit active, élévation hors de proportion de la PAP due à une augmentation du tonus vasculaire et un remodelage vasculaire (GTP > 12mmHg).
Le gradient entre la pression artérielle diastolique (PAPd) et la PAPO, qui est normal (≤ 5mmHg) dans les HP post-capillaires, n'est actuellement plus utilisé dans le diagnostic et l'évaluation des HP dans la dernière classification de 2008 (Dana Point 2008).
But :
- analyse des données cliniques, échocardiographiques et hémodynamiques des HP post-capillaires des patients référés dans un centre de référence d'HP - évaluer le rôle du gradient PAPd-PAPO dans la prise en charge des HP
Méthode :
Nous avons analysé de manière rétrospective les données cliniques, hémodynamiques et échocardiographiques des patients qui ont été diagnostiqué pour une HP au moyen d'un cathétérisme cardiaque entre janvier 2009 et juin 2011 au centre de référence d'HP du Centre Hospitalier Universitaire Vaudois (CHUV).
Résultats:
- 40% des patients ont les critères pour une HP post-capillaire - 33% des patients ont une HP qui répond à la définition d'HP "hors de propotion" avec un GTP
> 12mmHg - 74% des patients avec HP post-capillaire ont une cardiopathie gauche associée avec des signes
échocardiographiques de dysfonction diastolique - Sur les 27 patients avec une HP du groupe 2, 44% ont plusieurs facteurs de risque (FR) pour
une HP - 75% de ces patients avec une cardiopathie gauche ainsi qu'un autre FR pour une HP ont un
gradient PAPd-PAPO > 5 mmHg versus 8% de ceux qui n'ont pas d'autre FR (p-value 0.0075)
Conclusion :
Les HP post-capillaires sont fréquentes chez les patients adressés au centre de référence d'HP pour une suspicion d'HP. Dans notre cohorte 85% des patients avec HP post-capillaire ont une HP hors de proportion dont 44% ont un FR non cardiaque susceptible d'être à l'origine de l'HP. Le gradient PAPd-PAPO semble être un meilleur facteur discriminant que le GTP pour la caractérisation et la classification des HP
Role of Ferredoxin 3 in hydrogen metabolism in the hyperthermophilic archaeon Thermococcus kodakarensis, The
2022 Summer.Includes bibliographical references.Life faces innumerable challenges to cellular maintenance and reproduction, including access to sufficient energy. As such, all domains of life ubiquitously utilize energetically conservative mechanisms to maximize energy gains from the environment. Use of proteinaceous electron carriers, like ferredoxins, allows cells to harness energy from catabolic reactions that would otherwise be lost to the system as entropy or enthalpy. The hyperthermophilic, anaerobic archaeon Thermococcus kodakarensis is of particular interest as a target for bioengineering to maximize total energy gains, as it natively produces hydrogen gas resulting from terminal electron transport through a Membrane Bound Hydrogenase. T. kodakarensis encodes for three physiologically distinct ferredoxins. Prior to this thesis, only the sequence and molecular weight of the T. kodakarensis ferredoxins were known. Efforts in this thesis laid the groundwork for the biophysical characterization of each ferredoxin isoform via protein-film voltammetry and x-ray crystallography by the development of a reliable recombinant expression and purification scheme. Preliminary biophysical assay trials resulted in a Ferredoxin 1 crystal capable of diffracting to 1.1 Ångstroms, and midpoint reduction potentials for Ferredoxin 1 and Ferredoxin 3 confirming the predicted redox center geometry, demonstrating the efficacy of the developed protein expression and purification scheme for producing high-quality samples. Further investigation into the activity of the ferredoxins resulted in the generation of T. kodakarensis strains encoding for a tether protein between Ferredoxin 3 and its presumed sole electron acceptor Membrane Bound Hydrogenase at two respective locations. The parent strain includes a deletion of Ferredoxin 3, resulting in a deficient phenotype during sulfur-independent growth. The tethered strains of T. kodakarensis demonstrates a full recovery of sulfur-independent growth. Additionally, western-blotting revealed retention of the tethered protein in-vivo, and headspace measurements demonstrated restoration of hydrogen gas production compared to the parent deletion strain, and a reduction in total hydrogen gas output per cell compared to the lab parent strain. These findings implicate the importance of Ferredoxin 3 in hydrogen metabolism in T. kodakarensis and indicate Ferredoxin 3 as a potential target for bioengineering. Furthermore, this thesis is the foundation for further characterization of the T. kodakarensis ferredoxins as proteinaceous electron carriers with potential applications outside of this model organism
To be a Blue Squirrel
TIME had stopped for her. Here it was again—the old argu- -™- ment made of so many little ones—it had been gathering momentum for weeks. It batted its head against a brick wall and then plodded back for a fresh start..
Navy Personnel Enjoy Hearty Menus at Friley
Almost 900 men in navy blue pass through the double serving line in the Friley Hall dining room each mealtime and finish eating in one-half hour, according to Mrs. Dean Hossle, \u2741, who directs the food service, which is under the management of the Memorial Union. She plans the menus and supervises the kitchen and dining room
From a fashion-wise pedestal Vicky Views Veishea
Long before the mad whirl of Veishea, fashion-wise Vicky will select her new spring wardrobe. But she\u27s not thinking only of Veiseha days, she has a sharp eye out for the summer beyond. Vicky knows all the latest trends, but from then she selects for herself only those lines, colors and textures which bring out her best qualities
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